Scaffold cam lock construction

ABSTRACT

A locking connector for detachably securing a connecting member or brace to a frame part of a scaffolding, employs a gusset plate unit secured to the frame and provided with at least one latching slot portion. The end of the connecting member or brace carries a latching unit or device that is adapted to be removably introduced into the latching slot portion of the gusset plate. The latching device has a pair of spaced-apart flanges secured on a stub shaft, and a latching collar and a cooperating operating arm are rotatably carried on the shaft between the flanges. The latching collar has a centrally disposed flange and spaced-apart segmental or arcuate inner and outer pairs of lugs along the shaft secured on each side of the flange. The operating arm has a closed-end, elongated, slot portion that is adapted to ride on the inner pair of lugs for rotating the collar on the shaft. The gusset plate has an open slot entry passage or mouth portion of minimized entry extent through which the outer pair of lugs are adapted to be introduced when the lugs and the diametric spacing therebetween are aligned with the open mouth portion to expose the shaft between the restricted opening thereof. The open mouth portion is provided with inclined, outwardly diverging, entry edges along which the outer lugs are adapted to ride and roll in introducing the device into the latching slot portion. The gusset plate is provided with a cross wall portion against which an outer rounded flange of the pair secured on the shaft is adapted to engage and cooperate with the flange and the outer pair of lugs of the collar to provide a balanced aligning, inward rolling turning movement of the collar when the device is being introduced into a latching position.

United States Patent 11 1 Morris SCAFFOLD CAM LOCK CONSTRUCTION [75] Inventor: Ronald G. Morris, Beaver Falls, Pa.

[73] Assignee: Beaver-Advance Corporation,

Ellwood City, Pa.

221 Filed: May 13, 1974 21 Appl.No.:469,436

Primary Examiner-Andrew V. Kundrat Attorney, Agent, or Firm-Parmelee, Miller, Welsh & Kratz [57] ABSTRACT A locking connector for detachably securing a connecting member or brace to a frame part of a scaffolding, employs a gusset plate unit secured to the frame and provided with at least one latching slot portion. The end of the connecting member or brace carries a 1 June 10, 1975 latching unit or device that is adapted to be removably introduced into the latching slot portion of the gusset plate. The latching device has a pair of spaced-apart flanges secured on a stub shaft, and a latching collar and a cooperating operating arm are rotatably carried on the shaft between the flanges. The latching collar has a centrally disposed flange and spaced-apart segmental or arcuate inner and outer pairs of lugs along the shaft secured on each side of the flange. The operating arm has a closed-end, elongated, slot portion that is adapted to ride on the inner pair of lugs for rotating the collar on the shaft. The gusset plate has an open slot entry passage or mouth portion of minimized entry extent through which the outer pair of lugs are adapted to be introduced when the lugs and the diametric spacing therebetween are aligned with the open mouth portion to expose. the shaft between the restricted opening thereof. The open mouth portion is provided with inclined, outwardly diverging, entry edges along which the outer lugs are adapted to ride and roll in introducing the device into the latching slot portion. The gusset plate is provided with a cross wall portion against which an outer rounded flange of the pair secured on the shaft is adapted to engage and cooperate with the flange and the outer pair of lugs of the collar to provide a balanced aligning, inward rolling turning movement of the collar when the device is being introduced into a latching position.

12 Claims, 10 Drawing Figures SCAFFOLI) CAM LOCK CONSTRUCTION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to a self-aligning latching construction for detachably and securely connecting members of a scaffold-like assembly. An important phase of the invention pertains to facilitating the assembly of scaffold structural or tubing members by the employment ofa type of rolling entry of a latching device carried by the end of a brace member into an open-end latching slot portion of a gusset unit carried by another scaffold member.

2. Description of the Prior Art The Weisz US. Pat. No. 2,808.297 is illustrative of a cam lock construction to which the present invention pertains. Heretofore, it has been customary and necessary in effecting an assembly to, as shown in FIG. 1 of this patent, move an operating arm or handle to a fully horizontal position to assure an accurate alignment of a latching collar for laterally inserting it into a latching slot portion of a mounting gusset plate or the like. After entry (see FIG. 2 of the patent), the handle is then turned or dropped to a vertical position at which its locking end will engage within a locking recess provided in an upper portion of an innermost flange that is integral with the end of a brace member being connected.

Although this construction has had successful utilization, it has the disadvantage that a workman may have difficulty in providing the exact alignment of the collar that is essential in entering the device within the latching slot portion and particularly so, when his hands are cold in the winter or when wearing gloves. There has been a need in this connection for an improved type of entrance such that the workman in assembling a scarf fold can exert substantially his full effort in manipulating the connector member or brace, with a minimum of concentration on aligning the device before attempt ing to insert it within the latching slot portion of the gusset plate. That is, heretofore the opposed pair of spaced-apart latching lugs of the collar had to be accurately horizontally aligned with the open mouth portion of a sidewise-open latching slot, in order to introduce the device into a full latching position. This particularly presents a problem when a workman attempts to insert an upper end of a connector member or brace after its other end has been latched in position.

SUMMARY OF THE INVENTION The present invention deals with a solution to this problem in accordance with which the workman does not have to concentrate on accurate alignment of the members to be connected, and the latching device may be rolled or automatically rotated into full alignment with the most restricted portion of the open mouth of the latching slot portion of the gusset plate unit by ap plying entry pressure to the end of the connector member or brace. Using this system, it is no longer necessary to accurately align the upper end of the connecting member with the mouth of the slotted portion, since the rolling movement inherently accomplishes this result.

It has thus been an object of the present invention to solve the problem heretofore encountered in introducing a latching device into a latching slot portion of a gusset plate unit in connection with the assembling of scaffolding.

Another object of the invention has been to provide a strong and effective locking connector for particular use in the assembling and disassembling of scaffolding members and which will avoid the need for a full initial accuracy of alignment of the latching parts in accomplishing a latching assembly.

Another object of the invention has been to discover how to effect a substantially automatic aligning insertion of a connector device within a latching slot portion in connection with the assembling of scaffolding.

A further object has been to evaluate factors required in obtaining an effective detachable latching connection between scaffolding members and to discover how the structure required may be modified to provide a more flexible type of latching entry of the device within the latching slot portion of a gusset plate unit.

These and other objects of the invention will appear to those skilled in the art from the illustrated embodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmental view in elevation of a scaffold frame provided with a connector gusset plate unit. In this figure. dot and dash lines indicate a conventional prior art construction ofa locking gusset plate, particularly from the standpoint of the shape and relationship of front and mouth entry edge portions of its latching slot portion. The solid lines illustrate an improved construction of the present invention.

FIG. 2 is a view similar to FIG. 1 showing a preferred or optimum construction of a gusset plate unit.

FIG. 3 is a view similar to FIGS. 1 and 2 showing a further variation of a construction in accordance with the invention.

FIG. 4 is an exploded isometric view of a latching connector unit or device that is carried by an end portion ofa connecting member or brace for insertion into and out of latching relation with a gusset plate unit. such as illustrated in FIGS. 1, 2 and 3.

FIG. 5 is a fragmental side view in elevation and partial section on the scale of FIGS. 1 to 4, inclusive. showing the latching connector device of FIG. 4 in a fully assembled, operative relation on the end of a scaffold connecting or brace member.

FIG. 6 is a somewhat diagrammatic side view on the scale of the previous figures showing a first step in introducing the latching device of FIG. 5 through the mouth passageway or opening edge portions of a latch ing slot or eyelet formed in a gusset plate unit. In this position, a circular, outermost flange of the connector device is shown in sliding engagement with a front portion of a bottom wall of the gusset plate unit, and an outer pair of arcuate latching lugs carried by a latching collar are approaching rolling engagement between the opposed edges of the mouth or passageway, such that they may be turned in a counterclockwise direction to cause them to approach a parallel relation with a longitudinal axis of the open mouth portion of the latching slot and enable entry of the latching device therein.

FIG. 6A is a fragmental top plan view in partial section illustrating the initial starting position of FIG. 6.

FIG. 7 is a side view on the scale of and similar to FIG. 6, but showing a final step in the advancement of the latching device wherein an outer pair of its latching lugs are in substantially full alignment with the opening to the latching slot portion, as effected by rotation of such lugs by frictional engagement with sloped entry edges to the immediate entry opening or mouth portion. It will be noted that an operating handle is now in a substantially horizontal position, and that the shaft of the device is in an exposed or vertically aligned relation with respect to the immediate lip edges of the latching portion.

FIG. 8 is a view similar to FIGS. 6 and 7, but showing the handle of the latching device as being moved to a vertical position after the device has been fully inserted within the latching slot portion.

And FIG. 9 is a final latching position in which the handle is fully vertical and its locking lug has dropped into a locking recess in a stationary innermost flange at the end of the connector or brace member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Heretofore a gusset unit, as particularly illustrated by the dot and dash lines of FIG. I, was provided with entry ledge or lip portions a of considerable extent or length to thus define strong holding shoulders and an opposed pair of planar, horizontal, opposed, entry ledges having the same minimized width of entry spacing therealong and of considerable outward-inward extent. The dot and dash lines I illustrate the type of pla nar, vertical front entry walls that have been employed and their right angular relationship with the immediate entry ledges a.

In endeavoring to provide a solution to the problem of an improved type of entry of a latching device into a latching slot portion of a gusset plate unit, it was first determined that planar and forwardly extended thick ledges or shoulders (see a of FIG. 1) were not neces sary from the standpoint of strength considerations, since main separating forces are customarily exerted by a connecting or brace member 13 in a diagonal direction across a latching slot portion 15a. Also, applicant found that the front end portions of a gusset plate unit may be lengthened (compare 150 of FIG. 1 with b). It was discovered that a type of rolling movement of an outer or front pair of arcuate latching lugs 23 could be effected to do automatically, during entry advancing movement of a latching device, what had heretofore been required of the workman to do initially before such advancing movement. That is, it was determined that the latching device could be entered with its handle 24 at an angle and would not now have to be turned to an accurately aligned horizontal plane before attempting to enter it into the opening leading to a latching slot portion such as 15a.

This is accomplished by providing sloped guide edges 15c along which latching lugs 23 may roll, preferably by initially employing outermost flange 18 as a slide guide wheel for such movement and importantly, by minimizing the forward extent of immediate lip edge portions 15b or 25b. As shown in FIG. 6, the front edge of bottom or connecting wall 25f of a gusset unit such as 25 is adapted to be engaged by the front flange 18 to start a guidedin action of the latching device.

Although the optimum sloped angle of the forward edges (such as 150, 25c and 25:) was found to be about 45 with respect to the horizontal or an axial plane of entry, it was determined that this may vary within a range of about to 65. If the angular relation is too small or too great, then the rolling action cannot be accomplished. A highly efficient or optimum rolling action is accomplished when, for example, the arcuate outer convex curvature of the latching pair of lugs 23 approaches the curvature of the opposed pair of entry edges, such as 25c and 25e of the embodiments of FIGS. 2 and 3.

Since there are two latching lugs 23 to be entered (as shown in FIG. 6) in a somewhat angular or off-aligned relation, it is important to incline both the upper and lower entry edges, such as 15c. 25c and 25v or 25(- and 250' in such a manner that one. for example. the leading lug 23, will engage and roll along the upper surface edge 15c. 250 or 25 and/or the other, lower or backwardly positioned lug 23 will engage and roll along the lower edge 15c or 25c. The length of the inclined ride or guide edges 15c, 250, or 25c and 25e must be sufficient to enable such a rolling engagement by the pair of locking lugs 23 and as an optimum, a dual rolling engagement therebetween. The relationship may be reversed if, for example, the locking unit is to be entered from an upper angular relation rather than a lower angular relation such as illustrated in FIG. 6. Finally, it is important that there be, in effect, a rolling action that will assure a turning movement of latching collar 20 on the shaft 19, so as to align the opposed open spaces of the shaft 19 with the lip edges 151) or 25b to thus substantially align the pair of locking cams 23 in a front to back relationship with respect to a longitudinal axis of the passageway to the latching slot portion 15a or 25a,

as shown in FIG. 7. Front edge portions, such as 15c, 25c and 25e are lengthened to strengthen the open portions of the gusset plate unit 15, 25 or 25', and importantly, to provide a sufficient extent of rolling edge surface such that, as above pointed out, each one of the pair oflatching cams 23 may have a rolling engagement with an associated one of the edges 15c, 250 or 25a when the latching device is being entered into a latching slot portion such as 15a or 25a of a gusset unit.

In carrying out the invention, a gusset plate or latching box unit 15 (25 or 25) has been constructed in such a manner as to provide an immediate entry area, mouth or lip edge open portion 15b that represents an area of maximized restriction or minimum diameter open to the substantially circular latching slot portion 150, and provided with backwardly converging, forwardly diverging or sloped entry, guide or ride edge portions 15c. It is highly essential, as distinguished from the prior art constructions (see a, b of FIG. 1 of this disclosure and FIG, I of the Weisz US. Pat. No. 2,483,862), to minimize the forward extent of the immediate entry edge or lip area 15b in the direction of a longitudinal entry axis of the latching slot portion, such that substantially line edges are approached that serve as termini for the inclined guide-ride edges 150. An outer, stationary flange 18 secured on shaft 19 of the latching device not only serves as a sliding entry guide for the device, but also serves to balance a rolling type of entry-engagement of the latching lugs 23 on the inclined guide edges such as 15c, whereby an effective automatic turning-aligning movement of collar 20 which carries the lugs 23 may then follow until the lugs approach a substantially horizontal positioning such as illustrated in FIG. 7. The closely spaced relation of the stationary front flange 18 with respect to intermediate flange 21 of the collar 20 assures a continued guided advancing. rolling movement of the latching lugs 23 between the opposed edges such as 250.

Referring to FIG. I, the box-like locking gusset unit 15 is shown secured in position, as by weld metal w, in a corner position between a pair of scaffolding members, such as a vertical post and a horizontal rail or cross arm 11. As shown in FIG. 6A, a box-like unit, such as or 25 may be of upwardly U-shaped construction, as defined by an opposed pair of gusset plate vertical side walls, and a bottom, cross-extending or horizontal, connecting wall 25f. It will be appreciated that one or a pair of slotted side walls may be provided, but that the principles of the invention will be described, for the purpose of simplicity, from the standpoint of one side wall only, with the understanding that the same type of connection may be afforded for the other side wall of a unit or box, such as 15, 25, or 25' of FIGS. I to 3, inclusive.

Three embodiments of the invention have been shown as represented by FIGS. 1, 2 and 3. The embodiment of FIG. 1 illustrates a latching mount, gusset or locking plate unit 15 which has a pair of vertical, horizontally spaced-apart side plate walls connected by a bottom wall 15f (similar to bottom wall 25] of FIG. 6A). Each side plate or wall is shown provided with a latching slot portion 15a of circular shape, an immediate entry lip or mouth edge portion 15b of minimized entry diameter, and inwardly converging and outwardly diverging, upper and lower, inclined entry edge por tions 156 that terminate at their outer or front ends in relatively short-length, vertical edge portions 15d representing the depth of connecting end curvature of the cross-extending, bottom connecting wall 15f.

In the embodiment of FIG. 2, gusset plate unit 25 is also shown provided with a circular latching hole or slot portion 250 that has immediate entry mouth or lip edges 25b that represent the inner ends of the pair of outwardly diverging and convexly curved, upper and lower lip or mouth edge portions 25c. The edge portions 25c and 25e terminate at their ends in vertical edge portions 2511.

In the embodiment of FIG. 3, gusset mounting unit 25' is of the same construction as the embodiment of FIG. 2, except that the upper entry edge portion 250 is concavely rather than convexly shaped.

It will be noted from FIGS. 1, 2 and 3 that in all of the embodiments it is important and essential that the immediate mouth or lip edge portions 15b or 25b which represent the minimum diameter of entry for the latching device or unit should be of minimized extent in the direction of entry, as distinguished from a conventional gusset which inherently has a somewhat maximized extent, see a of FIG. I.

In FIGS. 4 and S, a latching device or unit has been illustrated as mounted on an offset end portion 13a of a connector or brace member 13. An inner disc-like head or flange 16 is carried on the end portion 130 and is secured thereto in a suitable manner as by weld metal w. The flange 16 has a pair of upper and lower locking recess or notch portions 160, one of which is adapted to be engaged by a backwardly bent, tip end, locking lug portion 24a of an operating arm, handle or lever part 24. The provision of a pair of oppositely positioned and aligned recesses 16a enables locking the handle 24 and its associated collar with respect to the back flange 16 independently of whether the member 13 is positioned in a downward, diagonally extending relation or an upward diagonally extending relationship in the scaffolding assembly.

The operating arm member 24 has a closed end elongated slot portion 24b which is adapted to be slidably positioned on a back pair of backwardly extending, segmental or arcuate, spaced-apart lugs 22 of latching collar 20. The lugs 22 have an outer curvature that corresponds to the end curvature of the slot 24b and the length of the slot is sufficient to permit the lug 24a of the member 24 to be raised or lowered sufficiently to clear a cooperating locking recess 16a.

The collar 20 has a centrally positioned ring-like guide flange 2I from which the pair of lugs 22 extend backwardly. The second pair of similar lugs 23 extend forwardly of the ring flange 2| and, as before explained, serve as latching lugs. A mushroom-shaped part 17 has a stub shaft 19 on which the collar 20 is rotatably positioned and has an extending mounting shaft portion 190 of reduced diameter which is adapted, as shown in FIG. 5, to extend through a central hole portion 16b in the inner, backwardly positioned flange l6 and to be secured in position therein by forming a swaged or enlarged head portion 19b. As also shown in FIG. 5, the inner flange 16 has a cooperating spacedapart relation with a front, outer, circular or ring flange 18 of the part 17 to define a mounting space for the collar 20 as well as for the operating arm 24.

With reference particularly to FIGS. 6, 6A, 7, 8 and 9, a locking operation has been disclosed which has been made possible by the present invention. In this connection, as shown in FIG. 6, the handle or arm 24 no longer has to be in a purely horizontal position when entering the device between the lips 25c and 252 of, for example, the optimum or preferred type of gusset plate unit 25. On the other hand, it is only initially necessary that the backwardly extending pair of lugs 23 be placed in operative rolling engagement between, for example, upper and lower edges 25c and 25: Thence, force may be exerted through the agency of the connector member 13 or the handle 24 so as to move the device further into the open space with an ensuing rolling action of the lugs 23 on the surfaces 25c and 25a The rolling action (as shown in FIG. 7) results in a turning of the collar 20 on the shaft 19 in a counterclockwise direction to thereby move the lugs 23 into a substantially fully aligned relation with the restricted opening defined by the edges 25b to permit the full entry of the locking device within the latching slot por' tion 25a. At this time, the handle 24 and the arcuate lugs 23 have attained a substantially horizontal positioning (FIG. 7). Thereafter, as shown in FIG. 8, the handle 24 may be rotated in a clockwise direction downwardly to thus move the pair of lugs 23 to a final upright or vertical latching positioning of FIG. 9. After the full latching position of the arrangement has been attained, the locking lug 24a may then fall into one of the recesses due by gravity or pull on the handle 24 to positively lock the device in its latched position within the slotted portion 25a of the cam box or gusset plate unit, such as 25. It will be noted that it" horizontal lines are drawn within the latching slot or hole portion 15a or 250 of FIGS. 1 to 3, inclusive, from the immediate lip edges 15b or 25b, that such lines will define a cross or vertical dimension in the FIGURES that is substantially less than the actual diameter of the latching slot or hole portion 15a or 25a. As indicated from a study of FIGS. 6 to 9, inclusive, it will be apparent that the width dimension or diameter of the spacing between the lips b or 25b of the entry mouth portion corresponds substantially to the outer diameter of the stub shaft portion 19 that is to be entered and is less than an outer diameter or cross dimension taken across the front entering pair of the pair of front. spacedapart, arcuate lugs 23 in their positioned or mounted relation on the shaft portion. For latching the device of FIG. 5 within the gusset 25 of FIGS. 6 to 9. inclusive, it will be apparent that it is essential that the width of the open mouth portion represented by 25b be smaller than the cross dimension or diameter between the pair of lugs 23, such that when, as shown, the device is entered in the latching slot 250, a rotation or turning of the handle 24 will cause the lugs 23 to reach a locking position within the latching slot. As shown in FIGS. 8 and 9, this occurs when the pair of lugs 23 are positioned in a substantially right angular relation with respect to the mouth portion 25b. If, for example, the width of the mouth portion between 25b corresponded to the maximum diameter of the latching slot or hole portion 250, then there would be nothing to prevent a sidewise-outward movement or release of the device of FIG. 5 from within the latching slot of the gusset plate 25. Thus, the construction makes it necessary to, as illustrated, enter the latching lugs 23 in an endwisealigned relation with respect to the open mouth portion 25b defined by the lip edges, in order to bypass or provide entry along the stub shaft 19 which has substantially the same diameter as the mouth portion.

As shown, the entry edges are configurated to facilitate an inward rolling movement of the pair of lugs 23 thereon into bypassing alignment with and through the open mouth portion of restricted width into the circular latching portion of enlarged width or diameter. it will also be noted that the entry edges, such as 256 and 25a, have a curvilinear configuration of substantially the same radius as the pair of arcuate latching lugs 23.

I claim:

1. In a locking connector construction for a scaffold frame or the like which has a latching gusset plate unit for securing on the frame and having a side wall provided with an open-end substantially circular latching slot portion therein; and which also has a latching device for securing on an end portion of a connector member of the frame for movement into and out of latching engagement with the latching slot portion, wherein the latching device has a back flange for securing on the end portion of the connecting member, has a stub shaft secured at its back end to extend from the back flange, has a front guide flange secured on a front end of the stub shaft, and has a latching collar rotatably mounted on the stub shaft between the back and front flanges; wherein the collar carries a guide flange and has a pair of front spaced-apart arcuate-shaped latching lugs projecting from a front side of the guide flange, and the device has a handle operatively mounted for turning movement with said collar; the improvement which comprises, an open entry portion from a front edge of the side wall of the gusset plate unit into the circular latching slot portion thereof, said entry portion being provided by a pair of outwardly diverging and inwardly converging entry edges intersecting said substantially circular latching slot portion to provide an open mouth portion and the maximum inward convergence of said entry edges substantially as a common line edge, said open mouth portion being immediately open to said latching slot portion and defining an opening therebetween of a width substantially corresponding to the diameter of said stub shaft and smaller than the diameter of said latching slot portion, said latching slot portion having a diameter that substantially corresponds to a cross dimension representing the outer diameter of said pair of arcuate-shaped latching lugs as positioned on said stub shaft, said pair of entry edges being configurated to facilitate an inward rolling movement of said pair of latching lugs thereon into bypassing alignment with and through said open mouth portion and into said latching slot portion, and said handle being adapted to thereafter turn said pair of lugs into a locking position within said latching slot portion.

2. A locking connector construction as defined in claim 1 wherein said pair of entry edges have curved surfaces toward said open mouth portion.

3. A locking connector as defined in claim 1 wherein an entry edge of said pair has a concave curvature adjacent to said open mouth portion.

4. A locking connector construction as defined in claim 1 wherein an entry edge of said pair has a convex curvature adjacent to said open mouth portion.

5. A locking connector construction as defined in claim 1 wherein both entry edges of said pair have a convex curvature towards said open mouth portion.

6. A locking connector construction as defined in claim 1 wherein, said pair of entry edges terminate at their innermost ends substantially immediately at said open mouth portion, and said pair of entry edges have curved surfaces therealong.

7. A locking connector construction as defined in claim 1 wherein said pair of entry edges have a curvilinear configuration towards said open mouth portion of substantially the same radius of curvature as said pair of arcuate-shaped latching lugs.

8. A locking connector construction as defined in claim 1 wherein said pair of entry edges are curved and have an angular slope towards said open mouth portion within about 20 to 65,

9. A locking connector construction as defined in claim 1 wherein said stub shaft along opposite sides thereof is exposed between said pair of latching lugs.

10. A locking connector construction as defined in claim 9 wherein, the flange of said collar carries a pair of back spaced-apart arcuate-shaped lugs extending from a back side thereof, and said handle has a closedend elongated slot portion operatively positioned on said back pair of lugs for rotating said collar to turn said front pair of lugs into and out of a locked position within said latching slot portion.

11. A locking connector construction as defined in claim 1 wherein, said gusset plate unit has a bottom wall extending from the side wall thereof, said front flange is of circular shape and is carried by said stub shaft in a forwardly spaced relation thereon with respect to said guide flange, and said front flange is adapted to initally guidably engage the bottom wall of the gusset plate unit when said latching device is being inserted and to cooperate with said guide flange to guidably maintain said pair of latching lugs in rolling engagement with said pair of entry edges during movement of said pair of lugs thercalong towards said open mouth portion.

12. A locking connector construction as defined in claim 11 wherein said gusset plate unit has an opposed side wall provided with a latching slot portion and an open entry portion of the same defined construction for receiving a latching device of the same defined construction within its latching slot portion. 

1. In a locking connector construction for a scaffold frame or the like which has a latching gusset plate unit for securing on the frame and having a side wall provided with an open-end substantially circular latching slot portion therein; and which also has a latching device for securing on an end portion of a connector member of the frame for movement into and out of latching engagement with the latching slot portion, wherein the latching device has a back flange for securing on the end portion of the connecting member, has a stub shaft secured at its back end to extend from the back flange, has a front guide flange secured on a front end of the stub shaft, and has a latching collar rotatably mounted on the stub shaft between the back and front flanges; wherein the collar carries a guide flange and has a pair of front spaced-apart arcuate-shaped latching lugs projecting from a front side of the guide flange, and the device has a handle operatively mounted for turning movement with said collar; the improvement which comprises, an open entry portion from a front edge of the side wall of the gusset plate unit into the circular latching slot portion thereof, said entry portion being provided by a pair of outwardly diverging and inwardly converging entry edges intersecting said substantially circular latching slot portion to provide an open mouth portion and the maximum inward convergence of said entry edges substantially as a common line edge, said open mouth portion being immediately open to said latching slot portion and defining an opening therebetween of a width substantially corresponding to the diameter of said stub shaft and smaller than the diameter of said latching slot portion, said latching slot portion having a diameter that substantially corresponds to a cross dimension representing the outer diameter of said pair of arcuate-shaped latching lugs as positioned on said stub shaft, said pair of entry edges being configurated to facilitate an inward rolling movement of said pair of latching lugs thereon into bypassing alignment with and through said open mouth portion and into said latching slot portion, and said handle being adapted to thereafter turn said pair of lugs into a locking position within said latching slot portion.
 2. A locking connector construction as defined in claim 1 wherein said pair of entry edges have curved surfaces towaRd said open mouth portion.
 3. A locking connector as defined in claim 1 wherein an entry edge of said pair has a concave curvature adjacent to said open mouth portion.
 4. A locking connector construction as defined in claim 1 wherein an entry edge of said pair has a convex curvature adjacent to said open mouth portion.
 5. A locking connector construction as defined in clailm 1 wherein both entry edges of said pair have a convex curvature towards said open mouth portion.
 6. A locking connector construction as defined in claim 1 wherein, said pair of entry edges terminate at their innermost ends substantially immediately at said open mouth portion, and said pair of entry edges have curved surfaces therealong.
 7. A locking connector construction as defined in claim 1 wherein said pair of entry edges have a curvilinear configuration towards said open mouth portion of substantially the same radius of curvature as said pair of arcuate-shaped latching lugs.
 8. A locking connector construction as defined in claim 1 wherein said pair of entry edges are curved and have an angular slope towards said open mouth portion within about 20* to 65*,
 9. A locking connector construction as defined in claim 1 wherein said stub shaft along opposite sides thereof is exposed between said pair of latching lugs.
 10. A locking connector construction as defined in claim 9 wherein, the flange of said collar carries a pair of back spaced-apart arcuate-shaped lugs extending from a back side thereof, and said handle has a closed-end elongated slot portion operatively positioned on said back pair of lugs for rotating said collar to turn said front pair of lugs into and out of a locked position within said latching slot portion.
 11. A locking connector construction as defined in claim 1 wherein, said gusset plate unit has a bottom wall extending from the side wall thereof, said front flange is of circular shape and is carried by said stub shaft in a forwardly spaced relation thereon with respect to said guide flange, and said front flange is adapted to initally guidably engage the bottom wall of the gusset plate unit when said latching device is being inserted and to cooperate with said guide flange to guidably maintain said pair of latching lugs in rolling engagement with said pair of entry edges during movement of said pair of lugs therealong towards said open mouth portion.
 12. A locking connector construction as defined in claim 11 wherein said gusset plate unit has an opposed side wall provided with a latching slot portion and an open entry portion of the same defined construction for receiving a latching device of the same defined construction within its latching slot portion. 